This invention relates to machines for loading ammunition automatically, and has particular reference to machines for loading shotshells, although the concepts of the invention are not limited in usefulness to that specific purpose. Machines of this general ty0pe serve to load empty shell casings automatically with preselected quantities of propellant and shot or other projectiles, and with wads and shot protectors of numbers and types appropriate to the intended use of the particular type of shell, to crimp or otherwise close the mouths of the shells, to carry out appropriate inspections at various phases of loading, and to reject improperly loaded shells.
An example of such a machine appears in U.S. Pat. No. 2,663,421 granted to W. S. Reynolds et al on Dec. 22, 1953, and assigned to the owner of the present application. Such known machines are well suited for continuous, high-volume production of shells of any given gauge and load specification, and are therefore economical for loading the types of shells in greatest demand. There is however a need to supply the less popular loads and gauges of shotshells, which are not required in sufficient quantities to utilize the output capacity of an automatic loading machine for any extended period of time. These types of shells must therefore be produced in job lots, and the loading machine's tooling must be converted from one load specification to another between each lot. Such a changeover requires an extensive shutdown period for known types of machines, whose designs are not inherently well adapted to facilitate these alterations. Consequently, the cost of production of the less popular loads and guages of shells is disproportionately higher than the cost of varieties which are in greater demand.
The improved machine employs a drive chassis which produces two principal motions. These are the intermittent rotation or indexing of a dial about an axis to transport shell casings successively to a series of circumferentially-spaced loading stations, and the reciprocation of ram means along the same axis to actuate tooling which performs various loading steps. These are the same principal motions carried out by known machines exemplified by the aforementioned U.S. Pat. No. 2,663,421. Additionally, various fixtures require other individual motions; these include, for example, powder and shot dispensers, transfer mechanisms for feeding empty shell casings to the dial, and rotary crimping fixtures. In known machines, the structural relationships and connections of the drive chassis, ram, and machine frame with various fixtures are too inflexible or too complex to permit easy rearrangement for loading shells of a significantly different specification.
It is an object of this invention to expedite the production of ammunition in limited quantities or job lots by simplifying the changeover of the tooling of automatic loading machines from one shell gauge or type of load to another. It is another object to provide an ammunition loading machine of an improved, versatile design which permits the ready replacement as a unit of a complete set of tooling by another complete set. The improved machine makes it feasible to keep on hand several complete tooling assemblies, or die sets, each prearranged for a different gauge or type of load, and to interchange die sets between the loading of job lots of widely different specifications. Additional advantages of the improved loading machine will appear from the following description.
Briefly, according the one aspect of my invention, I mount the dial, ram means, and appropriate tooling and fixtures on a base plate assembly. These elements comprise a die set. The chassis includes readily-detachable drive rod means for the ram means and indexing means for the dial. The die set may be disassembled from the chassis by lifting it as a unit off the chassis housing. A shell transfer mechanism incorporated in the drive chassis is arranged to remain in place when the die set is removed, since it is unnecessary to relocate the station of this mechanism when changing die sets.
The facility with which the die set may be joined and detached from the drive chassis is enhanced by several further improvements. Rather than being rotatably mounted on the drive chassis by a central shaft and bearings, the dial is formed as a ring, and mounted on the base plate assembly of the die set by roller means which serve not only as the dial bearings, but also cooperate with the indexing mechanism of the drive chassis to perform the function of indexing the dial.
This arrangement of the dial and roller means not only reduces the complexity of the mechanism by performing dual functions, but also permits a plurality of ram drive rods to be extended from the drive chassis upwardly through different regions of a stationary central portion of the base plate assembly. This affords inherently greater resistance to tilting of the ram means by bending moments applied to the tooling than would the conventional use of a single drive rod arranged on the central axis of reciprocation.
I also take advantage of the possibility of using multiple ram drive rods to operate two independent rams, the first being reciprocated at the full rate of the machine cycle to actuate the bulk of the fixtures and tooling, and the second at half the rate of the machine cycle. The second half-speed ram is used to operate powder and shot charging dispensers of a preferred type, known per se, in which a reciprocable charging slide has two metering chambers, one of which is charged with powder or shot from a hopper while the other discharges into a shell casing, at either end of the charging slide stroke. This allows a greater period for the slide to dwell at either end of the stroke, and thus more time for the powder and shot to flow completely into and out of the metering chambers, than with a single-acting charging dispenser having only one metering chamber.